Influences of trunk stability on exercise performance of closed kinetic chain of upper and lower limbs

[Purpose] This study aimed to examine whether trunk stability is related to closed kinetic chain motor performance of the upper and lower limbs. [Participants and Methods] In this study, 27 healthy male university students participated. Trunk stability was measured under two conditions, with and without rhythmic stabilization, as a proprioceptive neuromuscular facilitation procedure. The shortest time required to perform 20 push-ups and lateral step-up/-downs (closed kinetic chain motor performances) immediately after rhythmic stabilization or sitting rest (without rhythmic stabilization) was measured. [Results] Left and right trunk stabilities were significantly higher, and the time required to perform the closed kinetic chain motor task was significantly shorter under the rhythmic stabilization condition than that of the non-rhythmic stabilization condition. Regarding the relationship between the difference between the two trunk stability conditions and difference between upper/lower limbs closed kinetic chain exercise capacity conditions, left trunk stability correlated with each closed kinetic chain movement, whereas right trunk stability did not correlate with either movement. [Conclusion] Trunk stability was shown to improve closed kinetic chain exercise capacity in the upper and lower limbs, and stability of the trunk’s dominant side (here, left side) seemed to regulate.